Field of the Invention
The present invention relates to an apparatus and a process for introducing catalyst particles into a moving bed of catalyst.
Description of the Prior Art
Prior art introduces catalyst particles into a fluid catalytic cracking reactor by means of a stand pipe interconnecting a regenerator and the bottom part of a reactor of a fluid catalytic cracking unit. A stream of catalyst particles is thus passed by gravity from the regenerator into the bottom part of the reactor (liftpot) through the stand pipe and directed to the upper part of the reactor by means of (lift)gases and the feed to be converted.
A disadvantage of the use of a conventional liftpot, however, is that the catalyst particles only obtain the flow best suited for commercial catalytic cracking (i.e. plug-flow) after they have passed the riser over a substantial length.
It has now been found that catalyst particles can advantageously be brought in plug-flow at a far earlier stage, i.e. when the riser has only been passed over a very short distance, by employing as liftpot an apparatus comprising a housing provided with a particular passage for catalyst particles in the downstream part thereof. As a result thereof improved reaction patterns can be obtained in the reactor, resulting in improved yields of valuable products.